It is well known that most outdoor roasters, grills, and smokers sold in the market are not sufficiently energy efficient. In addition, many outdoor cookers and smokers are commonly unable to provide highly consistent levels of control and performance from one use to the next or even during the course of a single cooking operation. An outdoor roaster or grill will also typically be best suited for cooking only certain types and sizes of products within certain temperature ranges and cooking speeds. As a result, the performance of the device will be less than desirable when cooking products of a different size or type (e.g., meat, poultry, vegetables, prepared dishes, etc.) or when cooking at a different speed.
Unfortunately, the solutions to such problems used in indoor cooking systems often do not translate well to outdoor applications. For example, historically, traditional indoor gas or electric ovens were operated by heating the air inside an insulated cooking chamber to a temperature of from about 300° to 400° F. so that the food within the oven was cooked primarily by free convection. However, these traditional indoor systems were known to be very inefficient. Consequently, to provide improved thermal efficiency and faster cooking, electrical fan systems were added to these traditional indoor ovens in order to increase the air velocity within the cooking chamber and to thereby provide a significantly higher convective heat transfer coefficient.
But, the addition of an electrical fan system also increased the cost and the overall complexity of the oven system and, therefore, was not a viable option for most outdoor cookers. Moreover, suitable electrical power sources for operating such systems are frequently not available for outdoor applications. Also, the higher convective heat tends to dry out the food.
Recently, an alternative type of outdoor cooker referred to as a “Radiant Tube Broiler” was disclosed in U.S. Pat. No. 8,227,728. In this device, the outer wall of the cooking tube is heated by gas or electricity so that the food within the tube is cooked primarily by infrared radiant energy emitted from and reflected by the interior wall of the cooking tube. However, although the Radiant Tube Broiler is more efficient than many other outdoor cooking systems, and is also more efficient than the traditional indoor oven described above, it is not more efficient than a convective oven, particularly when the Radiant Tube Broiler is operated by gas heating, because the hot combustion gas produced in the Radiant Tube Broiler is discharged directly to the atmosphere immediately after flowing upwardly along the exterior of the cooking tube.
In addition to the above, a need also exists for an improved combustion assembly which can be used in or with an outdoor cooking and/or smoking apparatus for burning charcoal, wood, or other solid fuel. By way of example, a typical charcoal combustor currently used in the art is constructed in a manner such that a significant amount of excess air flows upwardly through the entire charcoal bed. As a result, not only must all of this excess air be heated, but the flow of air through the charcoal stack causes the entire stack to ignite and burn at once. Consequently, for extended cooking and/or smoking procedures, the charcoal must be frequently reloaded.
The operation of the prior art combustor is therefore both inefficient and inconvenient. Moreover, the heat and smoke produced by the prior art combustor varies a great deal during the cooking and/or smoking process and is, to a significant degree, substantially uncontrolled. When fresh charcoal is reloaded, the flames spread up the stack until the entire bed is on fire and a peak temperature is reached. Then, the heat energy and temperature produced by the combustor steadily decline so that the cooking temperature is significantly lower by the time that the charcoal must again be reloaded.